corrupt esent database in Windows XP Pro

[villandra]

My computer abruptly shut down and wouldn't get past loading hte mouse
before going black - for days. It crashed less catstrophically last
week doing something similar. What happened seems to depend on where
one looks.

It is now booting - sometimes, using an error booting routine, and
says it doesn't get a boot file.

It seemed to crash because Webshots or Google Update tried
unsuccessfully to write to something. After that everything just hung
and the system would do very little.

One error message has to do with PMEM and MCSTRM, which I guess are
inconsequential. My system tries to start two services the drivers
for which do not exist, and as nearly as I can find, the prcesses
don't exist either. They are found in my device manager, it says the
drivers can't be found. Complete Vipre virus scan found nothing.

One message, that I get in the System recover CD, says error creating
output file, ptdcomp.dat, SysInfoComp. Yes, I'm spelling that exactly
right. Google can't even infd either of those terms.

Finally I get Esent databse corruption, something to do with catdb,
which may be aprtly attached to something, possilby in a hidden root
folder. An attempt to open file catdb for read/ writeaccess failed -
being used by another process.

How do I fix it?

My system, when it boots up, is very unstable - prone to sudenly turn
off - and extremely slow.

The articles on this online might as well be written in Greek, some
promise discussions that aren't there, and most pertain to Windows
2000 and to various server versions of Windows. I'm running Windows
XP Pro.

by the way, I ran Checkdisk and it found nothing wrong.